1. Field of the Invention
The present invention relates to a temperature difference detecting element utilizing a Seebeck effect, and more particularly, it relates to a temperature difference detecting element which has an improved arrangement of its thermoelements.
2. Description of the Prior Art
Japanese Patent Laying-Open Gazette No. 114090/1979 discloses a thermal detector employing semiconductor thermoelements made of reducing titanium oxide. As shown in FIG. 11, this thermal detector is formed by a plurality of thermoelements, each of which comprises a plate type semiconductor substrate 1 of reducing titanium oxide provided with ohmic metal films 2a and 2b on one major surface thereof. A hot junction 3 and a cold junction 4 are defined between the semiconductor substrate 1 and the ohmic metal films 2a and 2b. FIG. 11 is a plan view of three thermoelements 6a, 6b and 6c, which are connected in series with each other by lead wires 7 and 8 to provide an integrated thermal detector.
Its output voltage can be increased by connecting the plurality of thermoelements 6a, 6b and 6c in series with each other as shown.
In order to obtain the thermal detector shown in FIG. 11, however, it is necessary to separately prepare the thermoelements 6a to 6c, which must be alternately arranged in opposite directions as shown in FIG. 11 and then connected in series with each other via the lead wires 7 and 8. Thus, the steps of manufacturing the thermal detector are complicated.